Brian Kolfage, a Florida military veteran, recently convinced Americans to donate millions of dollars for a privately built wall on the U.S. southern border. Now he has jumped into a new venture: hawking millions of protective face masks that are in critically short supply during the coronavirus pandemic.

About a month ago, Kolfage formed a business called America First Medical, which offers on its website and in social media pitches to broker large-volume sales of high-grade masks known as N95s. He said he charges about $4 each ¡ª several times the prepandemic prices but a few dollars less than some hospitals, nursing homes and first responders are now paying.

Though he hasn¡¯t yet found buyers, Kolfage says he¡¯s found masks all over the world, including stockpiles hidden away in warehouses in Japan and Eastern Europe. If a deal goes through, he will collect a commission between 1 percent and 3 percent, depending on the size of the order, he said.